Quasiconvex function vs. Quasiconcave function

Hi,

For those who easily get confused about the definitions of these classes of functions,  you are not alone :-) Often, it is better to remember the definition for one of the two; and then use the result that "A quasiconcave function is a function whose negative is quasiconvex, and astrictly quasiconcave function is a function whose negative is strictly quasiconvex" to know about the other. You can find more about this here. 

Torben